Solar Panel Temperature Measurement

Solar panels are made up of solar cells which convert light into electricity that can be used to power many items ranging from handheld devices to supplementing the main power grid. The power output by solar panels is measured in watts or kilowatts. Since single solar panels cannot generate kilowatts of energy, most solar panels being used to supply power grids are set up in large arrays to provide the maximum power possible to the grid. It is important to monitor and estimate the amount of power being provided to the power grid.

Solar panels operate over a wide range of voltages and currents which determine the power output. It is possible to determine the maximum power that the solar panel can deliver by changing the resistive load applied to the solar panel or array. The maximum power point is the point where the solar panel applies the most power to the device or power grid. The temperature of the solar panel affects the maximum power output directly. As a solar panel's temperature increases, its output current increases exponentially while the voltage output is reduced linearly. Since power is equal to voltage times current this property means that the warmer the solar panel the less power it can produce. The power loss due to temperature is also dependent on the type of solar panel being used. For example, many common crystalline silicon solar panels can lose power at a rate of 0.50%/°C, while high efficiency solar panels lose power at a rate closer to 0.35%/°C. In an industry that focuses on the most cost efficient technologies in terms of cost per generated power it is extremely important to know when a solar panel is performing poorly compared to expectations.

One method of monitoring solar panel temperature is to use a flat surface temperature sensor like the WE710 to take measurements. Flat surface temperature sensors can be mounted on each solar panel or on selected representative solar panels to provide temperature measurement profiles of the solar panel array. A flat surface temperature sensor will provide temperature measurement data to an overall monitoring system allowing staff to be notified in advance of potential power output issues caused by changes in a solar panel's temperature. With this measurement information adjustments can be made to the power delivery system or the whole power grid if necessary.

For information on sizing smaller solar panel arrays please click Here.